Home » Public Forums » GMCnet » Assessing coach - valves stuck and bad stuff happened
| Assessing coach - valves stuck and bad stuff happened [message #213635] |
Sun, 07 July 2013 18:46  |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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Senior Member |
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So, I got the brakes functional and took coach for local spin. three spins actually, totaling about ten miles. Ran great. second trip noticed some clicking, thought "sticky valve will loosen up". This morning trying to start was loud click, almost pop for a few turns, and then "rrrck pop" a number of times. When it finally fired, it ran baaaad.
compression test, very sad. front two cylinders nearly nothing. I pulled driver side valve cover - number 1 intake valve doesn't even move so at least the rocker and rod are trash (correct my terms or ask questions if anything sounds off, it may be I'm saying it wrong), I'm afraid for potential cam damaged. Coach sat for nearly 8 years, this engine was rebuilt 3000 miles before it sat.
Questions/next steps:
1. Do I have to take the whole AC compressor and brackets to get the passenger valve cover off?
2. Can I try replacing the rocker and pushrod and try to free the valves? If so, how to free valves?
3. Tests? Fixes? What do I do with other cylinders to prevent more?
Throw in some encouragement with advice, I'm needing it...Thanks in advance.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Assessing coach - valves stuck and bad stuff happened [message #213639 is a reply to message #213635] |
Sun, 07 July 2013 20:09  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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Was this an engine with old gas in the tank? If so, I'd bet the varnish glued valve stems to the guides and you bent pushrods. I've had that happen with small engines a couple times. Old gas evaporated and leaves a varnish behind. New gas dissolves the varnish into the fuel and it can get deposited on the valve stems. Everything is fine when the motor is hot but when you shut it off, the varnish turns back to glue and you're screwed.
A neighbor works with a guy that bought an old car with a tank full of old gas. When he drained the gas, he didn't want to just throw it away so he put it in his Chevy pickup. Drove to work the next day and it ran fine but that afternoon it did the same thing you describe. Lots of bent pushrods.
Yes, you have to remove the compressor mount. The easiest way is to take a sawsall and cut through the stud. The process is described here:
http://www.gmcmhphotos.com/photos/g6356-ac-bracket-fix.html]
I thought I'd done something new but found out that it had been done before by lots of folks. Makes it much easier.
It's also described and discussed in this forum thread:
http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&goto=205160&rid=2555#msg_205160]
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
[Updated on: Sun, 07 July 2013 20:18] Report message to a moderator |
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| Re: Assessing coach - valves stuck and bad stuff happened [message #213643 is a reply to message #213639] |
Sun, 07 July 2013 20:45 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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Senior Member |
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Yes, there was some gas in the tanks. I added some new to dilute it but didn't want to fill it, as I fixed the filler hose which had been leaking, and didn't want to find out it wasn't fuel proof by new gas running out. The fuel drain plugs would not come out, and I wasn't thinking I needed to do the electric fuel pump mod I read about, because I didn't think it would whack up the engine like this.
I definitely appreciate the links to the AC mod.
Will I need to remove the head, or just replace the bent stuff with the valve covers off? Anyone know a good web page to teach me the whole routine with spring compressor tools and stuff if that is the direction i'll need to go? Can I use solvents to unstick?
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Assessing coach - valves stuck and bad stuff happened [message #213690 is a reply to message #213635] |
Mon, 08 July 2013 10:50 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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PM sent
Dennis
| Tilerpep wrote on Sun, 07 July 2013 18:46 |
So, I got the brakes functional and took coach for local spin. three spins actually, totaling about ten miles. Ran great. second trip noticed some clicking, thought "sticky valve will loosen up". This morning trying to start was loud click, almost pop for a few turns, and then "rrrck pop" a number of times. When it finally fired, it ran baaaad.
compression test, very sad. front two cylinders nearly nothing. I pulled driver side valve cover - number 1 intake valve doesn't even move so at least the rocker and rod are trash (correct my terms or ask questions if anything sounds off, it may be I'm saying it wrong), I'm afraid for potential cam damaged. Coach sat for nearly 8 years, this engine was rebuilt 3000 miles before it sat.
Questions/next steps:
1. Do I have to take the whole AC compressor and brackets to get the passenger valve cover off?
2. Can I try replacing the rocker and pushrod and try to free the valves? If so, how to free valves?
3. Tests? Fixes? What do I do with other cylinders to prevent more?
Throw in some encouragement with advice, I'm needing it...Thanks in advance.
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: Assessing coach - valves stuck and bad stuff happened [message #214071 is a reply to message #213635] |
Thu, 11 July 2013 17:54 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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Senior Member |
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Whew! Three long stressful days, and I may be out of the woods. A blacklister put me in touch with Dick Paterson - wow what a huge thank you I owe him!
So the not so short version maybe with some tips to pass along.
My AC compressor bolts were easy to manage, so no extra cutting there. took AC Compressor rear bracket that bridges valve cover off and the lowest tension tightener bolt, and didn't even touch front bracket. Compressor hung by the bolt that goes between front and rear bracket, basically in it's normal place minus the rear bracket that was in the way. also took off alternator bracket to be able to get valve spring compressor on #1. Had earlier removed spark plugs to do compression test
Pulled valve covers. Yanked out #1 and #2 intake pushrods with a crowbar and two visegrips holding onto them. Was scared of engine/head death at this point.
At Dick Paterson's suggestion, I started with a spring compressor, ball peen hammer (should have been brass I read, but smacked it gently with what I had) and alternated between carb cleaner and Marvel Mystery oil on the top side of the valves. His opinion for cause was not bad gas but combo of bad oil and sitting for eight years. It was clear it was the stems that were stuck rather than the seats. As they freed up, I kept repeating -motion, solvent and oil. Ordered new regular non hardened pushrods (so they would crush again as sacrificial link if continued problem) and replaced pushrods that sounded wonky rolling on glass (about eight - two were ruined, six more were a little off). Ran it on the starter alone and continued Marvel oil and motion - turn over a few times and oil 'em up (maybe ten times over five hours)(careful with AC belt still there but not on compressor). put new oil in crankcase and put it all back together. ran for a half hour at and near idle (ran about a cup of ATF through the carb to lube valves from air flow side as well - neighbor came over to see "if we were alright" sooo smoky!). Let it sit overnight. This morning started right up, had a little miss/maybe sticking but not bad. Smoothed out after about two minutes.
Ran pretty well, had some trouble with a restart that a jump solved - which still lends to electrical not quite right. I have cleaned the battery grounds to engine and positive from battery to battery boost solenoid.
So now onto the fridge that lit up first time and now doesn't, and the house water systems!
Blessings and thanks to all who chipped in. (I also realized some who sent me notes directly to email got tossed by Hotmail into junk folder, so now I can watch there too). Time will tell if this process will be enough...
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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